Composite Structural Member

ABSTRACT

A light-weight composite structural member including an elongated body having at least one internal recess with a tensioned cable in the recess or series of recesses. End pieces on each end of the elongated body secure the cable, which is connected to each end piece. The composite structural member is light-weight with relatively thin walls while providing enhanced benefits for resisting the combination of tension, compression and buckling forces.

BACKGROUND

This disclosure relates to a structural member constructed for strength in tension and compression. More specifically, the structural member includes a composite body with an internal cable for added benefits.

Load bearing structural members often have elongated bodies, and must be light-weight for certain construction projects. Applications include structures that must be constructed by hand, such as in remote or military applications, such as for cranes assembled on oil rigs. As such, certain structural members must not be heavy while still being able to handle appropriate loads and forces.

Aluminum extrusion pieces, such as shown in U.S. Pat. No. 6,561,571, have been used for structural members requiring strength in compression and axial forces. Aluminum is known to form many hard, light and corrosion-resistant alloys for use as structural members.

Also, U.S. Pat. No. 6,539,679 discloses a light-weight structural member with a strength-reinforcing flat steel strap. The steel strap extends along the length of the structural body, and it transfers load outwardly toward the opposing portions of the structural body. Anchor plates at opposing ends of the structural body hold the strap in tension. The pre-tensioned strap is secured in tension to opposing ends.

Next, various cables have previously been used in tension, but not in the same structural member arrangement of the present disclosure.

SUMMARY

The present disclosure provides a light-weight composite structural member. The composite structural member is light-weight while providing enhanced benefits for resisting a combination of tension, compression, and buckling forces.

A composite structural member includes an elongated body having one or more internal recesses with a tensioned cable in one recess or a series of recesses. End pieces on each end of the elongated body secure the cable to the body. Each end piece may include an aperture and adjustable means to secure the cable in tension. The cable may also provide an additional safety factor for the structural member.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features of this disclosure and the manner of obtaining them will become more apparent, and the disclosure itself will be best understood by reference to the following descriptions of structural members taken in conjunction with the accompanying figures, which are given as non-limiting examples only, in which

FIG. 1 shows a perspective view of a composite structural member;

FIG. 2 shows an end and shortened length view of the structural member;

FIG. 3 shows a cross sectional view of the member of FIG. 2;

FIG. 4 shows a partially cut away view of an end of the structural member;

FIG. 5 shows a perspective exploded view of a structural member having a single internal cable;

FIG. 6 shows a view of an end of the single-cable structural member;

FIG. 7 shows a cross sectional view of an end of the structural member;

FIG. 8 shows a top view of a composite structural member;

FIG. 9 show a cross sectional view of FIG. 8 taken along A-A;

FIG. 10 shows an exploded view of the composite structural member of FIG. 8 with interconnecting connectors and preloaded cable; and

FIG. 10A shows a detail of the connectors and cable from “B” of FIG. 10.

The exemplifications set out herein illustrate embodiments of the disclosure that are not to be construed as limiting the scope of the disclosure in any manner. Additional features of the present disclosure will become apparent to those skilled in the art upon consideration of the following detailed description of illustrative embodiments exemplifying the best mode of carrying out the disclosure as presently perceived.

DETAILED DESCRIPTION

While the present disclosure may be susceptible to embodiments in different forms, the figures show, and herein described in detail, embodiments with the understanding that the present descriptions are to be considered exemplifications of the principles of the disclosure and are not intended to be exhaustive or to limit the disclosure to the details of construction and the arrangements of components set forth in the following description or illustrated in the figures.

As shown in FIG. 1, a composite structural member 10 includes an elongated body 12, end pieces 14 and 16 located at first and second ends of the elongated body 12, and one or more internal tension members, such as cables 18 that can be connected in tension to the end pieces 14 and 16. The elongated body 12 includes a generally linear central longitudinal axis and at least one internal recess 20 that can accommodate the cable 18. Various complementary components combine to produce structural and functional properties not present in any individual component.

The elongated body 12 can be preloaded to resist compression or lateral forces. The elongated body 12 preferably includes internal spaced walls 22 for added reinforcement and strength. As shown in the drawings, certain internal walls 22 can be perpendicular to the outer surface 24 of the elongated body 12. Additional internal walls 26 can be concentric with or parallel to the outer surface 24 of the elongated body 12.

The elongated body 12 preferably has a plurality of internal recesses 20 extending from the first end to the second end of the body 12 and that are capable of enclosing a plurality of internal cables 18. As shown in FIG. 3, the elongated body 12 includes two cables 18 in opposite internal recesses 20 that are formed between internal walls 22, the outer surface 24 of the elongated body 12, and additional internal walls 26.

The elongated body 12 is preferably preloaded extruded aluminum with a cover mantle 30, such as carbon fiber, S glass fiber, a thin swaged layer of steel or Kevlar, on the outer surface 24. The cover mantle 30 can additionally assist with resisting forces of compression and buckling.

The end pieces 14 and 16 are preferably end caps that preferably completely cover each end of the elongated body 12. The end pieces 14 and 16 can be respectively secured to each end of the elongated body 12 by a variety of means, including welding, friction fit, cable tension or fastening plates 32. As shown in FIGS. 1-4, particularly FIG. 4, the fastening plate 32 can be secured to an end of the elongated body 12 and to an internal head plate 34 by fasteners 36, such as bolts. As shown in FIGS. 2 and 4, the head plate 34 can pass through an aperture or slot in the end piece 14.

As such, the end pieces 14 and 16 are respectively connected on each end of the elongated body 12 by fastening plates 32 fastened to head plates 34 that pass through each end piece 14 and 16. An end portion of the elongated body 12 is secured between the fastening plates 32 and the head plates 34. Preferably, the fastening plates 32 and head plates 34 are friction fit with the elongated body 12 and secured, such as by a bolt 36. The fastening plates 32 and head plates 34 may be clamped and loaded together on a portion of the elongated body 12 so hard that they should not move under normal load. The head plate 34 passing through the end piece 14 and 16 transfers force on the end pieces 14 and 16 to the outer wall 24 of the elongated body 12 and prevents rotation of the head plate 34 and/or end pieces 14 and 16 with respect to the body 12.

The end pieces 14 and 16 preferably cover each end of the elongated body 12 and may include a functional piece 38, such as a socket, collar or pin holder for use in making a connection with another structure. The end pieces 14 and 16 may have an aperture 40 capable of serving as a cable hole through which each end of the cable 18 are connected to each end piece 14 and 16. Preferably, at least one cable aperture 40 includes a means for preloading the cable with tension 42, such as including an incised threaded rod, i.e. a helically advancing threaded screw and washer. The means for preloading the cable 42 includes various screws and washers. A cable head 44 may be included that is secured to an end of the cable 18 as part of the means for preloading the cable 42. Other means to fasten and preload the cable include the cable being threaded on a small pulley with a rack and pawl to load the cable 18 and keep it from unwinding.

The cable 18 is connected to each end piece 14 and 16 and can be adjusted as a pretensioned cable fitted between the end caps 14 and 16. The cable 18 can be stretched under pretension and affixed to end caps 14 and 16 at both ends of the structural member 10, passing inside the internal recess 20.

In another embodiment shown in FIGS. 5-7, L-shaped extruded aluminum pieces 50 can be assembled to form a long square elongated body 12, such as a strut or brace. The series of hollow L-shaped pieces 50 are assembled to form a long square member. The L-shaped pieces 50 can have at least one internal spaced wall 22 for added reinforcement. The pieces 50 are assembled with a single central recess 20 for the tensioned cable 18 fitted between end caps 14 and 16 with an aperture 40 capable of serving as a cable aperture through which each end of the cable 18 is connected to each end piece 14 and 16. With the cable aperture 40, a means for preloading the cable with tension 42, such as a screw, can be used. A cable head 44 secured to an end of the cable 18 is shown in FIG. 5. As detailed above, the cable 18 is preferably stretched under pretension and affixed to end pieces 14 and 16 at both ends of the composite structural member 10.

Per the example shown in FIGS. 5-7, four pieces 50 (preferably extruded aluminum) are light and thin walled. Each extruded piece 50 is reinforced hollow “L” shaped in the cross-section with internal and external vertexes. These pieces 50 collectively form a square and help resist against buckling. It is possible that these four pieces 50 could be inside another square structure or wrapped or otherwise secured together by a cover mantle 30, such as tape (spiral or cigarette wrapped), carbon fiber layers, a thin swaged layer of steel, or a Kevlar coating.

In the center of the four pieces 50, an insert 60 can be wedged as shown in FIGS. 5 and 7, in which the cable 18 can also pass to handle tension. The insert 60, preferably steel, can be wedged in the center of the four pieces 50. The insert 60 has a base structure, preferably a hollow square, with protrusions extending from four sides (somewhat like a symbol in cross section), which each extend between two adjacent extruded pieces 50. A wedge insert 60 can be preloaded for handling compression. The four pieces 50 and wedge insert 60 are well suited for compression.

FIGS. 8-10 show a composite structural member 10 with interconnecting pieces 62 that can interconnect to form various shapes of the structural member 10. As shown, interconnecting pieces 62 have a plurality of openings 64 that are able to accept a corresponding attachment 66 of an adjacent piece 62. The preferred interconnecting connectors as shown have three T-shaped slots as openings 64 with a complementary T-shaped ridge that slides into a T-shaped slot as the attachment 66 of an adjacent piece 62. These pieces 62 can be extruded aluminum. The cable 18, such as wire rope, can be preloaded to provide additional safety and stability, such as against buckling and holding end pieces, 14 and 16, together. Four cables 18, one is each corner of the elongated body 12, can be connected to end pieces 14 and 16. Each end piece 14 and 16 may have cable apertures 40 used in conjunction with a means for preloading the cable with tension 42, such as a hex nut as shown, for securing the ends of a cable 18. Pieces 62 forming an elongated body 12 can be inside a cover mantle 30, such as carbon fiber, S glass fiber, a thin swaged layer of steel or Kevlar, on the outer surface 24. The cover mantle 30 can additionally assist with resisting forces of compression and buckling as well as cover any unused opening 64 of the various pieces 62.

For each embodiment, the components can be made of any suitable material. The elongated body 12 is preferably metal, ideally aluminum, but could be made of plastic or other materials. The cable 18 can be a wire rope formed from steel or a fiber rope, and may be cord formed from various materials.

The multipurpose structural member 10 can be adapted for various uses. While functional pieces 38 may dictate uses for the composite structural member 10, the member 10 may be used in a variety of applications as struts, braces, support, props and beams for various structures as tension or compression components. The composite structural member 10 provides benefits for resisting a combination of tension, compression, and buckling forces.

This disclosure has been described as having exemplary embodiments and is intended to cover any variations, uses, or adaptations using its general principles. It is envisioned that those skilled in the art may devise various modifications and equivalents without departing from the spirit and scope of the disclosure as recited in the following claims. Further, this disclosure is intended to cover such variations from the present disclosure as come within the known or customary practice within the art to which it pertains. 

1. A composite structural member including: an elongated body having an internal recess; end pieces on each end of the elongated body; and a cable connected to each end piece, the cable passing inside the internal recess; wherein the tensioned cable is fitted between the end pieces.
 2. The structural member of claim 1 wherein the elongated body additionally includes internal spaced walls for added reinforcement, which form part of the internal recess.
 3. The structural member of claim 1 wherein the elongated body is formed from extruded aluminum with a cover mantle including a glass fiber or carbon fiber covering.
 4. The structural member of claim 1 wherein the elongated body has a plurality of internal recesses with a plurality of internal cables.
 5. The structural member of claim 4 wherein two cables are in opposite internal recesses.
 6. The structural member of claim 1 wherein the end pieces are connected on each end of the elongated body by fastening plates fastened to head plates that pass through each end piece wherein a portion of the elongated body is secured between the fastening plates and the head plates.
 7. The structural member of claim 1 wherein the end pieces cover each end of the elongated body and have a cable aperture through which ends of the cable are connected to each end piece.
 8. The structural member of claim 7 wherein at least one cable aperture includes a means for preloading the cable with tension.
 9. A light-weight composite structural member including: an elongated body having preloaded thin walls and including internal walls forming part of an internal recess; end pieces covering each end of the elongated body; and a tensioned cable connected to each end piece, the tensioned cable passing inside the internal recess; wherein the tensioned cable is fitted between the end pieces and at least one end piece has a cable aperture through which an end of the cable is adjustably connected to the end piece having the cable aperture.
 10. The structural member of claim 9 wherein the cable aperture includes a means for preloading the cable in tension.
 11. The structural member of claim 9 wherein the end pieces are connected on each end of the elongated body by fastening plates fastened to head plates that pass through each end piece wherein a portion of the elongated body is secured between the fastening plates and the head plates.
 12. A structural member including: an elongated body having a first end, a second end, and an internal recess extending from the first end to the second end of the body; a cable located within the recess of the body, the cable having a first end and a second end, the second end of the cable being coupled to the second end of the body; a first end piece coupled to the first end of the body, the first end of the cable being coupled to the first end piece; whereby the cable is adapted to be coupled to the first end piece in tension to thereby preload the body.
 13. The structural member of claim 12 wherein the body includes a plurality of internal recesses and one or more cables, each cable having a first end coupled to the first end piece and a second end coupled to the second end of the body.
 14. The structural member of claim 12 including a second end piece coupled to the second end of the body, the second end of the cable being coupled to the second end piece.
 15. The structural member of claim 12 wherein the cable comprises a wire rope.
 16. The structural member of claim 12 including one or more head plates attached to the first end of the body, each head plate extending into a respective aperture in the first end piece, whereby the head plates inhibit rotational movement of the first end piece with respect to the body.
 17. The structural member of claim 16 including one or more fastening plates, each fastening plate being connected to a head plate, the body being located between the head plates and fastening plates.
 18. The structural member of claim 12 wherein the first end piece includes an aperture, the first end of the cable extending through the aperture.
 19. The structural member of claim 18 including an adjustment mechanism attached to the first end of the cable, the adjustment mechanism adapted to selectively tension the cable.
 20. The structural member of claim 19 wherein the adjustment mechanism comprises a threaded member threadably attached to the first end of the cable. 